The Dual Nipkow Disk Confocal Microscope and High Speed Confocal Imaging: New Designs, New Cameras, and New Capabilities.

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The introduction of a dual Nipkow disk scanning head should facilitate confocal microscopic study of live specimens. The use of micro-lenses in this design improves the Z-axis resolution, scan speed and overall optical efficiency of the original Nipkow disk design. Advantages of this device include the capability for high speed scanning (360 scans/sec), real time viewing, superimposed transmitted light and confocal imaging, together with reliable optical alignment, and a compact modular scan head that attaches to the video port of existing microscopes. When used with low light & light amplified cameras, lower power densities can be used to illuminate live specimens resulting in longer experiments being successfully completed.

The schematic diagram shows the optical path and specifications of the new scan head. A pre-aligned collimated light beam illuminates the upper micro-lens disk array. Each lens within the array focuses light through a small pinhole aperture on the lower Nipkow disk providing confocal multi-point scanning of the specimen. Fluorescent light emitted from the specimen passes back through the pinhole apertures to the dichroic mirror located between the two rotating disks. The dichroic mirror reflects the confocal image into the detector path. The confocal image can be observed directly through a 10x ocular or relayed to the camera port. The camera is chosen to achieve the desired combination of speed, dynamic range and spatial resolution. The acquisition, display, and recording aspects of the system are matched to the camera and are readily available. Limitations of the system include a fixed Z-axis resolution determined by the objective lens and pinhole size.